.mask {
  background: #fff;
  position: absolute;
  width: 100%;
  opacity: 0;
  display: none;
  transition: opacity 5s;
  transform: none;
}
.present > .mask {
  display: block;
  opacity: 0.7;
}
.step.present {
  z-index:1;
}
.pos_top {
  top: 0px;
  padding-top: 1000px;
  margin-top: -1000px;
}
.pos_bot{
  padding-bottom: 1000px;
}

.hidden {
  opacity: 0;
}

#impress .step .exitfocus {
  opacity: 1;
}
#impress .step .exitfocus.substep-visible {
  opacity: 0.5;
}
#impress .step .neverfocus:where(.substep-active, .substep-visible) {
  opacity: 0.5;
}

#impress .step .subhide {
  display: none;
}
#impress .step .subhide.substep-visible {
  display: revert;
}
#impress .step :is(.substep-visible, .was_substep) + .suberase {
  display: none;
}

#impress .step.future + .reveal {
  opacity: 0;
}
#impress .prevent_reveal.step:is(.present, .past) + .reveal {
  opacity: 0;
}
#impress .step.present + .reveal {
  opacity: 1;
}
#impress .step + .reveal {
  transition: opacity 5s;
}
#impress .step {
  transition: background 0.5s;
}
#impress .step.present {
  background: rgba(255,255,255,0.6);
}

body.impress-mouse-timeout div:is(.impress-progressbar, .impress-progress) {
    display: none;
}